$(function() {
    $(".n")
        .mouseover(function() { 
        	idelem = $(this).attr('id');
        	idelemdiv = idelem.replace('t-', 'm-');
        	$(idelemdiv).addClass('selected');
        })
        .mouseout(function() {
            idelem = $(this).attr('id');
        	idelemdiv = idelem.replace('t-', 'm-');
            $(idelemdiv).removeClass("selected");
        });
});